Shaft bearing

ABSTRACT

In a shaft bearing comprising outer and inner parts with an elastic element carrier disposed therebetween, the elastic element carrier includes first and second elastic elements disposed on opposite radial sides thereof and is movable with respect to one of the outer and inner parts in axial direction and with respect to the other of the outer and inner parts in radial direction, and the elastic elements disposed between the element carrier and the outer, and respectively, the inner parts have selectable elasticities so as to provide for distinct selectible radial and axial resiliencies of the shaft bearing.

BACKGROUND OF THE INVENTION

The invention relates to a shaft bearing comprising an outer part and aninner part and an elastic element including an elastomer materialdisposed between the outer part and the inner part.

DE 28 51 018 A1 and DE 41 39 923 A1 discloses shaft bearings whichinclude an outer part, an inner part and an elastic element including anelastomer material disposed between the outer part and the inner part.The outer part and the inner part are each in the form of hollowcylindrical support rings; the elastic element disposed therebetween isin the form of a rotationally symmetrical integrally formed bellows. Thebellows accommodates axial as well as radial shaft bearing forces. Thespring stiffnesses in radial and axial directions are thereforeinseparably interconnected.

It is the object of the present invention to provide a shaft bearingwherein the spring stiffnesses in axial and in radial directions of thebearing can be selected independently of each other.

SUMMARY OF THE INVENTION

In a shaft bearing comprising outer and inner parts with an elasticelement carrier disposed therebetween, the elastic element carrierincludes first and second elastic elements disposed on opposite radialsides thereof and is movable with respect to one of the outer and innerparts in axial direction and with respect to the other of the outer andinner parts in radial direction, and the elastic elements disposedbetween the element carrier and the outer, and respectively, the innerparts have selectable elasticities so as to provide for distinctselectible radial and axial resiliencies of the shaft bearing.

Preferably, the first and the second elastic elements are arrangedcircumferentially uniformly distributed.

In an advantageous embodiment of the invention, the element carrier hasradially inner and radially outer support areas distributedcircumferentially, wherein the first elastic elements are disposedbetween the radially inner support areas of the element carrier and theouter part and the second elastic areas of the elastic element aredisposed between the radially outer support areas of the element carrierand the inner part.

The first and the second elastic elements may be arranged alternately inthe circumferential direction.

Furthermore, the first and/or second elastic elements may be vulcanizedonto the element carrier.

In a particular embodiment of the invention, the second elastic elementsare attached to the element carrier in a form-locking manner.

The element carrier can be formed by a metal sheet member or a cast or amolded structure. It is manufactured for example by a fine castingprocess, an aluminum pressure casting process or a plastic injectionmolding process.

Preferably, the axial end side walls of the second support areas of theelement carrier extend radially inwardly and, if the element carrier isa metal sheet member, comprises inwardly bent plate structures by whichthe second elastic elements are held by the element carrier in aform-locking manner so as to prevent axial displacement of the elasticelements.

The second elastic elements may be in the form of ring segments. In apreferred embodiment of the invention, the three first elastic elementsand the three second elastic elements are alternately arranged in thecircumferential direction.

An embodiment of the invention will be described below on the basis ofthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a view in an axial direction of a shaft bearing according tothe invention,

FIG. 1 b shows the bearing in an axial cross-sectional view, wherein anouter part, an inner part and an elastic element carrier disposedbetween the outer and inner parts is visible,

FIG. 2 shows, in a perspective view, the outer part of the shaft bearingof FIG. 1, including an element carrier and the areas accommodating theelastic elements,

FIG. 3 shows the inner part of the shaft bearing of FIG. 1 including theelastic elements disposed on the inner part and,

FIG. 4 shows the element carrier of the shaft bearing of FIG. 1.

DESCRIPTION OF A PARTICULAR EMBODIMENT

The shaft bearing, the components of which are shown in FIGS. 1 to 4comprises an outer part 1, an inner part 2 and an elastic elementcarrier 5 with elastic elements 3,4 disposed between the outer part 1and the inner part 2. The elastic element carrier 5 engages the firstelastic elements 3 and second elastic elements 4 and retains thembetween the outer part 1 and the inner part 2.

The outer part 1 and the inner part 2 are each in the form of hollowcylindrical bodies. The element carrier 5 has three circumferentiallydistributed first support areas 51 and three radially more outwardlydisposed second support areas 52 of which the first support areas 51extend radially further inwardly than the second support areas 52.Between the radially inner first support areas 51 of the element carrier5 and the outer part 1 first elastic elements 3 are arranged and betweenthe radially outer second support areas 52 of the element carrier 5 andthe inner part 2 the second elastic elements 3 are arranged. In thefigures, three inner first support areas 51 and three outer secondsupport areas 52 are shown, for receiving the three first elasticelements 3 and the three second elastic elements 4 which are arrangedalternately and circumferentially distributed.

The radially outer second support areas 52 of the element carrier 5 havepartially cylindrical outer surface areas adapted to the inner surfaceof the outer part which they abut slidingly so that the element carrier5 is radially supported by the outer part but axially movable therein.

As apparent particularly from the lower part of the cross-sectional viewof FIG. 1 b, the first elastic elements 3 are formed by bellowselements, which accommodate the axial movement occurring between theelement carrier 5 and the outer part 1 because, as described, theseparts are axially movable relative to one another but, at the same time,radially supported relative to each other.

The second elastic elements 4 are formed by elastomer blocks which arespecifically designed for accommodating radial movements. Theseelastomer blocks 4 are clearly visible in the upper part of thecross-sectional view of FIG. 1 b and in FIG. 3 in a perspective view.

As also shown in FIG. 1 b and FIG. 3, the elastomer blocks 4 areprovided with bores 6 which extend through the elastomer block in theaxial direction of the shaft bearing and via which a certain radialresiliency of the elastomer blocks can be provided or is adjustable.These bores 6 as well as other openings or recesses can be providedselectively in various dimensions and configurations.

In the shown embodiment, the first elastic elements 3 in the form ofbellows elements are vulcanized to the inner side of the outer part 1and also to the outer side of the first support area 51 of the elementcarrier 5 which is disposed radially further inwardly. In this way, astable, play-free and durable connection of these bellow elements to theouter part 1 and the element carrier 5 is established. Furthermore, inthe embodiment shown, the second elastic elements provided in the formof elastomer blocks are vulcanized to the outside of the inner part 2.In the embodiment shown herein, the second elastic elements 4 which areformed by the elastomer blocks are attached to the element carrier 5 or,more accurately said, to the inner side of the second support areas 52thereof which are arranged further outwardly and with which they areengaged in a form-locking manner. To this end, the element carrier 5,which is shown alone in FIG. 4, is formed from a metal sheet which, atthe axial ends of the radially outwardly projecting second support areas52, is provided with radially inwardly bent cover plates 53, 54 by whichthe elastomer blocks 4 are axially retained and held in form-lockingengagement with the element carrier 5.

In this way, shaft bearings with different properties can be provided byassembly techniques whereby, on one hand, the components formed by theouter part 1, the element carrier 5 and the vulcanized bellows elementsforming the first elastic elements 3, the elastomer blocks forming thesecond elastic elements 4 and the inner part 2 are joined so as toprovide for different axial an radial spring resiliencies. For theestablishment of the different spring resiliencies of the elastomerblocks 4 vulcanizing tools may be used with correspondingly differentinserts can for providing different suitable diameters and/orarrangements of the bores and the recesses 6.

In the embodiment shown, the second elastic elements 4, which are formedby the elastomer blocks, have the shape of segments of a circular ring.The bellows forming the first elastic elements 3 have the shape shown inFIG. 1 b in cross-section. Instead, the first and the second elasticareas 3, 4, however, may have other shapes. Also, the elastic areas foraccommodating radial movements may be provided on the outside and theelastic areas provided for accommodating axial movement may be providedon the inside of the element carrier 5.

Furthermore, the elastic elements which are mainly provided for theaccommodation of radial movements and the other elastic elements whichare mainly provided for the accommodation of axial movements may, to acertain degree, also be capable to accommodate axial and, respectively,radial movements.

1. A shaft bearing comprising an outer part (1), an inner part (2)disposed within the outer part (1), an elastic element carrier (5)disposed between the outer part (1) and the inner part (2), firstelastic elements (3) disposed between the element carrier (5) and theouter part (1) and second elastic elements (4) disposed between theelement carrier (5) and the inner part (2), said first and secondelastic elements having different spring rigidities, and said elementcarrier (5) being supported so as to be movable mainly axially withrespect to one of the outer part (1) and the inner part (2) and mainlyradially with respect to the other of the inner and outer parts (1,2).2. The shaft bearing according to claim 1, wherein the first and thesecond elastic elements (3,4) are arranged uniformly distributed overthe circumference of the shaft bearing.
 3. The shaft bearing accordingto claim 2, wherein the carrier element (5) includes distributed overthe circumference thereof radially inner first support areas (51) andradially outer second support areas (52), said first elastic elements(3) being disposed between the radially inner first support areas (51)of the element carrier (5) and the outer part (1) and the second elasticelements (4) being disposed between the radially outer second supportarea (52) of the element carrier (5) and the inner part (2).
 4. Theshaft bearing according to claim 2, wherein the first and the secondelastic elements (3, 4) are arranged alternately in circumferentialdirection.
 5. The shaft bearing according to claim 1, wherein the outerpart (1) has a hollow cylindrical inner surface and the radially outersecond support areas (52) of the element carrier (5) includes partialcylindrical outer surface areas adapted to the hollow cylindrical innersurface of the outer part (1) so as to be supported thereby in such away that the element carrier (5) is radially supported and axiallyslidable in the outer part (1).
 6. The shaft bearing according to claim1, wherein the first elastic element (3) is formed by bellows elementsaccommodating axial movements.
 7. The shaft bearing according to claim1, wherein the second elastic element (4) includes elastomer bodies foraccommodating radial movements.
 8. The shaft bearing according to claim7, wherein the elastomer bodies (4) for the accommodation of radialmovements include recesses, openings or bores (6) for providing acertain radial resiliency.
 9. The shaft bearing according to claim 8,wherein the elastomer bodies (4) include a number of bores (6) extendingparallel to the shaft bearing axis.
 10. The shaft bearing according toclaim 8, wherein the recesses, openings or bores (6) have at least oneof different sizes and different arrangements.
 11. The shaft bearingaccording to claim 1, wherein the first elastic elements (3) arevulcanized to the outer part (1).
 12. The shaft bearing according toclaim 1, wherein the second elastic elements (4) are vulcanized to theinner part (4).
 13. The shaft bearing according to claim 6, wherein atleast one of the first and the second elastic elements (3, 4) isvulcanized to the element carrier (5).
 14. The shaft bearing accordingto claim 1, wherein the second elastic elements (4) are supported by theelement carrier (5) in a form-locking manner.
 15. The shaft bearingaccording to claim 1, wherein the element carrier (5) is one of a sheetmetal component, an aluminum pressure casting, a fine casting and aplastic injection molded component.
 16. The shaft bearing according toclaim 3, wherein the support area (52) of the element carrier (5)includes end walls (53, 54), which extend radially inwardly and by whichthe second elastic elements (4) are engaged in a form-locking manner forpreventing axial movement of the second elastic elements (4) relative tothe element carrier (5).
 17. The shaft bearing according to claim 1,wherein the second elastic elements (4) have the shape of segments of acircular ring
 18. The shaft bearing according to claim 1, wherein threefirst elastic elements and three second elastic elements are providedand alternately arranged distributed over the circumference of the shaftbearing.